Sphering, AKA Zorbing, is one of the craziest activities on earth - and in Lodz it's perfectly suited to the terrain! Make like a massive hungover hamster by fitting yourself into a giant inflatable ball and rolling down a hill, into water - basically wherever you want. You're in a huge bouncy bubble, and the world can't hurt you.
Stag parties in Lodz are a great opportunity to do stuff you've never had a chance to do before, and probably won't ever get the chance to do again. Like finding out what pool balls feel like just before they drop into the pocket, or being the rock that nearly squishes Indiana Jones in Raiders of the Lost Ark. Yell with insane laughter as the world outside rotates past at up to 30mph, with all your senses telling you that what you're doing is both impossible and dangerous. In fact, it's neither - strapped in securely and surrounded by acres of padded, air filled plastic, you couldn't be safer if you tried.
You'll come out gagging for another go - so it's just as well you get at least two bites of the cherry. Amazing.