So far we are on season 6 and I am a massive fan and I hope it goes on for a long time to come!!!!
The first series centers around 4 young phycists (Sheldon, Howard, Raj and Leonard) who meet a waitress/ aspring actress who has moved in to Sheldon and Leonards building. The humour is based around their two worlds meeting in the middle. We see the nerdy antics of the scientists followed by the often doomed love life of the 'cooler' penny. However, there is an ongoing love story 'will they wont they' saga between Penny and Leonard.
Later on in the seasons we see other secondary characters introducted. Howards love interest Benadette and Sheldons love interest Amy. Both scientists also, but add to the group dynamic perfectly.
This combination of actors and actresses work together brilliantly. It is a hilarious sitcom which never fails to make you laugh.
A lot of the jokes can be very science based, however I don't think you have to know much about science to enjoy the program.
It started in 2007, and you can see that some of the earlier episodes are slighted dated (visually, in terms of quality of picture). However, That does not detract from the humour of the program

Creators:
Chuck Lorre, Bill Prady. (Chuck Lorre is the same guy that created Roseanne and Two and a half men)
starring :
Johnny Galecki ,Jim Parsons ,Kaley Cuoco , Simon Helberg and Kunal Nayyar .
Jim parsons role as Sheldon cooper is particuarly brilliant, he has won numerous Grammys for his aclaimed performance!!

Overall, I would highly recommend this to everyone!