The guys and gals at IKEA Hackers don't half come up with some ingenious hacks for DIY cheapskates: here's one for our cyclist readers that will keep those underwear-wetting splashes to a minimum.
To make the below bicycle splash guard, all you need is an OMSORG shoehorn from IKEA (RRP: $0.99), some rubber bands and a clamp to hold it in place. It works exactly like a commercial splash or mud guard for bikes, such as this one. The idea is to protect your lower body from spray caused by your back wheel; particularly when it's raining.
As a non-cyclist, I'm not sure why you'd want to protect your heiny from splashes during torrential rainfall -- but seeing as these things can sell for over $50, I guess there must be some benefit.