Has anyone entered one of these events before? Whats the general consensus about it? when and wear did you do it and what sort of format was it? Well organised?

Doing the River Rat Race this weekend, there's no riding in this one but it looks like a good format so should be fun.

Done loads – good fun, generally well organised (they had some issues in the early days, but mostly sorted now). That's from the perspective of the sharp end of the field – I also know the organisors, and they do tend to listen to constructive criticism – though the impression I've always got from those further back is similar. Plenty on here who'd complain the biking isn't gnarly enough (London is certainly doable on a cross bike, arguably on slicks), but that's not really the point.

The impression I get is that the RRR is rather different – though I'm sure it will involve much of the same sort of stuff. Assuming you're not aiming to win, my top tip is not to take it too seriously.

Well there is no bikes on the river, obviously but it all looks good..

Like you say, not taking it seriously there is a few of us doing and just going to plod round having a laugh..