I l once made a diy floating ramp out of pine & some kids floates & set it up in the river . My first attempt didnt happened just as l was approaching for the jump my ramp sank.
Many poleys would argue the most ridiculous thing they have done is tried kiting. 
This is an easy one for me.
I used to WS at a lake in California, Lopez Lake. The sailing part of the lake has small mountain ridges that run along both sides of it, with a thermal wind that blows up the canyon, across the lake, in between them.
One day around 1987'ish, a bunch of us were waiting around for the wind to blow as predicted, but it was very slow in coming and we were getting anxious. Then some very dark clouds move in, but it started to finally blow, we were out on the water in record time having a pretty good time.
Then came the lightening and the thunder, we could see bolts coming down along both ridges on both sides of the lake, but we kept sailing. Mind you this was in the late 80's, and most of us were using aluminum masts, out in the middle of the lake, with lightening going on very near. Not only were we complete idiots for doing that, but it's amazing that none of us got fried.
I would never do that again.
Trying a freestyle trick even after my brain had said "I cant work out how they did that" 
Going windsurfing on the Peel inlet as a cyclone strength storm was approaching, given that we had been directed by the houseboat company to get our houseboat to the safety and shelter of the river ASAP. When the clouds got really black I decided to pack up and the mad dash to the river (at 5 knots) was made in dark and stormy conditions where we could barely make out the next channel marker through the driving rain. It was very exciting...
Trying to sail under the wind of a chopper hovering in the bay. Needless to say a massive fail. The sail or me couldn't quite figure out how to handle 20 knots of wind coming from directly above. 
Had a good laugh at your comment Bundy, so good I thought I would show my wife. "Funny" was one word serious tone reply. But I'm already at 6 boards so I suppose I don't have to think about it.
Headed off on a long cruise in light wind with an 8m sail when 30kt was forecast.
Sold all my windsurfing gear 5 years ago to go kitesurfing only to change my mind and have to buy all new gear 2 months ago.
Seeing how long I can sail for full speed with my eyes closed heading into shore.
(Hmm probably a good idea to keep clear of me when im out sailing)
I also like to do it walking to work (keeping my eyes closed that is) ive only hit a few poles and stumbled off the kerb a few times.
Sailing in a thunderstorm back in the 80's- pelting rain and no visibility. Rain lifted and I found out the wind had veered 360 degrees . As I had followed it I was blasting flat out into the shallows and shore 50m away..
Forgetting the fin of my big slalom board so setting my 9m cam sail on my 96 L freestyle board in 12 knts... Does not work and you do look stupid as well.
Posting on an ozzy windsurf forum 
and 2nd most ridiculous thing: attempting to surf head high+ waves on bic melodies using uphauls as legropes
I once went sailing and thought "This board is going like a dog today." It just wouldn't get planing although there was enough wind. I returned to shore, and flipped the board over thinking I might have weed on the fin. Not weed, I had left the fin cover on!
Open ocean sailing, overpowered on a Race sail and slalom board.
Very humbling experience
Believing Seabreeze/BOM forecasts and rigging for the forecast, not what the actual weather is.
Another lap at 3am around Narra Lake in the 24 hour One Design race back in the 80's. Huge thunderstorm brewing out west and sky looking decidely green. JUST made it back to Jammo Park as the lightning started.
Wednesday night twilight racing at Rodd Point Sydney with an impending thunderstorm - back in the late 80s. Fleet of about 30 or so.
Did not think too much about it at the time while racing, but when lightning flashed overhead it had a definite impact on the fleet. The lads with carbon or alloy masts said their hands and arms were tingling for a long while afterwards. The boys on the Windsurfers with fibreglass masts had no such after effect. We called the race off by that stage. One of the older boys had to be calmed down as he was pretty shook up by it. Said he thought he was going to die........
With hindsight, I guess we should never have set out. Lucky but stupid!
I can't claim this, but 4 of my friends in the 80s sailed Wallys from Marmong Pt to Chain Valley Bay on Lake Macquarie. They then carried their boards and rigs cross country over the pacific highway to lake Munmorah (about 3 Kim's). They then sailed across lake Munmorah to Budgewoi, then up the channel to Lake Tuggerah then across Northern part of Lake Tuggerah to Canton and then finally across the southern half of Tuggerah to The Entrance. 3 of them took about 14 hrs on the water. One of them spent the night on his board just south ofr Canton Beach and finished the next day.
Select to expand quoteMcSmurfin said..
Posting on an ozzy windsurf forum
and 2nd most ridiculous thing: attempting to surf head high+ waves on bic melodies using uphauls as legropes
and yet you have done so 44ish times
Select to expand quoteMobydisc said..
Believing Seabreeze/BOM forecasts and rigging for the forecast, not what the actual weather is.
And how often do we do that? 
Select to expand quoteJohn340 said..
I can't claim this, but 4 of my friends in the 80s sailed Wallys from Marmong Pt to Chain Valley Bay on Lake Macquarie. They then carried their boards and rigs cross country over the pacific highway to lake Munmorah (about 3 Kim's). They then sailed across lake Munmorah to Budgewoi, then up the channel to Lake Tuggerah then across Northern part of Lake Tuggerah to Canton and then finally across the southern half of Tuggerah to The Entrance. 3 of them took about 14 hrs on the water. One of them spent the night on his board just south ofr Canton Beach and finished the next day.
I seem to have heard of that! Amazing..
Insert old quavering voice..'When I was young we were real windsurfers we used to ...'
Select to expand quoteNotWal said..
Headed off on a long cruise in light wind with an 8m sail when 30kt was forecast.
I was wondering why anyone would feel motivated to red thumb an innocuous post like that.
It just occurred to me that it may well be yet another example of Macro assuming I'm picking on him.
If I'm wrong Macro please accept my apology. If I'm right get over it FFS. It's not about you.
ridiculous or dangerous ??
tried to windsurf on snow with an F2 Comet
yeah, like that was gonna work
since then built an ice sled and many, many versions of the snow sled
the first year broke my shoulder on the ice - guess that was the most dangerous
out on ice with a prototype sled in 30 to 50 km winds and a 7-oh battened sail
was going faster than i ever had on water - obviously - duh ...
I found a floating door on the Murray River when I was camping with mates and after a few beers I accepted the dare to sail it from Yarrawonga to Mulwala using my Wally rig.
I made it easy.
We then took it behind a boat and went skiing on it.
Tryed kiting on one occasion on the swan river (peli pt) many years ago ended up nearly on the causeway.
Said out loud "one more run" after a 3hr session in open ocean chop-hopping...
...30min swim in from out the back after mast broke.
Select to expand quoteNotWal said..NotWal said..
Headed off on a long cruise in light wind with an 8m sail when 30kt was forecast.
I was wondering why anyone would feel motivated to red thumb an innocuous post like that.
It just occurred to me that it may well be yet another example of Macro assuming I'm picking on him.
If I'm wrong Macro please accept my apology. If I'm right get over it FFS. It's not about you.
testing....
