Netwinner's one of my faves. It takes 25,000 points minimum to cash out for a $25 giftcard. That may seem like a lot, but 1) the site is totally FREE; 2) the game is simple (even a Cave Man can do it
, so you can do it while you surf the 'net or whatever; 3) the forum offers additional contests for extra points; and 4) a new twist to the game offers random multipliers for 2x, 5x, 10x or 25x your win (points only). I've played since last September and have earned almost 200,000 points since then.
The cash prizes include a jackpot for $1,000,000+. Monday, June 25, would be a great day to try it out (as DLK pointed out)--it's the birthday bash and multipliers will be active on EVERY click, from noon - midnight EDT.
*****UPDATE***********
Netwinner's no longer my fave! On 5/12/08, they abruptly canceled pending prize redemptions and converted them back into points. They also deleted the one remaining point redemption for a sure thing (the 100,000 point in exchange for $100 E-count card/reload). My $200 approved redemption became 400,000 points to blow on raffles! Netwinner, you don't pay so we won't play! If your prizes were cancelled, take action!
CompareRewards Netwinner: We Played; They Scammed Us All