My cousin took me for a ride in his V8 offroad buggy this afternoon, and he managed to roll it on it's side. Apparently he's never done that before, and he's a really experienced driver. No damage done to us or the buggy, but when we didn't come back my uncle came after us on the quad and then went off to get help. He turned around a little too fast in long grass, and then hit a large rock, which sent him flying and the bike flipping over a few times. He's got a bit of a concussion and he was quite disoriented for a while, but he's very lucky the thing didn't land on top of him (on in the side of my dad's car, who'd just turned up as he crashed). My other uncle's a doctor, so he kept an eye on him. None of us were wearing helmets. Didn't make any difference in the buggy (open fields and the only danger was rolling, not hitting trees), but it would have made a big difference on the quad. I had my first experience of riding one though, as someone needed to take it back up to the shed afterwards. I took it slow - 2nd and 3rd gear. Don't like it at all - wheel track's not wide enough to keep it the right way up. Much rather be on two wheels.