Chess is fun, especially if you can play at the level you are at
For beginners Chess.com is a good free site and requires no downloads.
Some of the world’s best players play at ICCas well as PlayChess – These are basically pay sites.
Another site for more advanced levels is chess.net which claims to be “the BEST place to play chess online, chat, and meet new friends all around the world.” I will let you be the judge but I did get great feedback about them recently.
Please feel free to rate these sites and add your comments so others can benefit from your knowledge.