Drunk crazy times. Awesomeness. Yes, probably comparable to a spring break in Mexico. It can be pretty awesome, you just have to be prepared. SPF 50 sunblock applied every 1-2 hours, shoes (old tennis shoes work best or water shoes), water, snacks, and of course lots of beer!! :)
Also,, I've never used a sheet, I just flip my tube in the water occasionally
Tips:
Watch for rapids. Pay attention because you will need to lift your butt a couple of times to miss rocks.
Ziploc anything you don't want wet.
LOTS of sunscreen. IMPORTANT. Seriously - one year I was burned so bad it was purple-red. Yikes! I learned my lesson and last time I went I didn't even hardly burn at all.