I say you have a good strategy.  Next time you see them ask if you can join them.  

As for meeting other new people, the easiest way to meet them would be to go hang out somewhere that you enjoy.  If you enjoy reading, go to the coffee house in Barnes & Nobles (or wherever), or like you said before, join a club.  Clubs are the easiest way to meet new people and make great new friends.

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Even if I'm the only one laughing its still worth doing.  
Because, in a world of moral ambiguity, laughter, though
fleeting, is the only certainty.