check out http://www.clamocracy.com/crimecenter/?rid=25943, friend just showed me it and it's epic. you can easily get a free rapidshare within an hour or shitloads of paypal money. they're only doing this for a short time so hurry the fuck up.
they pay you to get people to signup in their forums. 10 signups = free rapidshare account or $1.2 per signup on forums via paypal. fast as hell. my account is currently pending. i nearly have enough referrals for 2 accounts.
it's probably even better than adsense since it pays $1.2 per referred signup on the forums. it just takes a bit of work to convince people to register with your referral number.