Tombola
Tombola offers free and fun ways to play games for prizes.  Each week on their site they are giving away at least $15,000 in cash prizes.  Each game is easy to play and won't take much time.  The games include instant scratch-type tickets and the like.  You'll know immediately if you've won a prize!

BingoNet
If you love bingo, then you're going to love BingoNet!  Join for free and collect "Bingo $'s" that you can redeem for prizes in the Prize Store, or you can pay a reasonable monthly fee of US$4.95 and earn "Gold Bingo $'s" which entitle you to cash prizes and other benefits.  You get to play at three different bingo sites by joining as well.  There are many variations on the bingo theme here, and they usually change the games to suit the "season" (i.e. at Christmas they have a Christmas type bingo with reindeer, snow and Xmas carols playing!) and other themed bingo games (i.e. such as "Sweetheart Bingo" where the scoreboard has little cherubs and when you mark your card it becomes a heart).  Some of the regular games include "One Line Bingo", "Speed Bingo" - where the balls are called fast and furiously, and a "Progressive Bingo" whereby if no-one wins the "pot", it is rolled over to the next game and so on until someone wins, just to name a few!

Lotto Tour
Play 10 times each day for a chance to win up to US$2 million.  They also offer a "Multiplier Madness" option, whereby if you refer your friends and they win, say, US$1 million, you win the same amount!  Another great free lotto site I play at daily.

Lotto 749
Pick 7 numbers and you could win up to US$1 million.  You get to play 5 times per day on this site, and of course, it's all completely free.

LottoBreak
Are you the impatient type that hates waiting to see if they've won?  Well then, you'll appreciate LottoBreak.  You can play lotto up to 15 times per day on this site for a chance to win up to US$100,000.  Just pick 7 numbers, click on the submit button, and in about 30 seconds, you'll find out if you've won!

Gamesville
Got a bit of time up your sleeve?  Then pay a visit to Gamesville!  Here you can play a variety of free games and win cash prizes.  The games include many versions of bingo, slots, blackjack, poker, and many other unique games.  A great site to waste a bit of time on!

Big Prizes
This site is owned by Jackpot.com and there are plenty of games here to keep you amused, such as instant scratch tickets, a few great versions of solitaire, a slot machine, plus you can enter the "Million Dollar Lotto" once daily for a chance at US$1 million.  All games (with the exception of the "Million Dollar Lotto") pay you with "Prize Points" that you can enter in daily, weekly and monthly draws to win cash and prizes.

Huge Prize
Another free site where you can play games and win prizes.  Games on offer include various forms of slot machines, poker, blackjack, bingo, scratch tickets, lotto and a few different versions of solitaire.  You play for "Power Points" which you can enter in the draws for a daily prize of US$25, a weekly prize of US$100 and a monthly prize of US$500.

You Win Trivia
Like trivia?  Love cash?  Well then this site is for you!  You get to play five trivia games per day to earn points. Each day they pay the top three winners (or "Daily Trivia Masters", as they refer to them) cash prizes of US$250, US$150 and US$100 respectively.  Each month, the Grand Masters Award goes to the player who has earned the most points.  Plus each of their Daily Trivia Masters and Monthly Grand Masters will automatically be entered into their tournament for the Trivia World Champion for US$1 million.

Pogo
Another great game site.  Join Pogo for free and play a variety of games to win cash prizes.  You can choose from slot machines, poker, keno, bingo, various gameshow-type games, trivia games, crosswords and many more.  The only downside to this site is that at this point in time, only US and Canadian citizens are eligible to play for prizes, however if you just want to waste some time playing some fun games, then this is a good site to visit.