Anyone who grew up watching "Sesame Street" on public television will quickly be able to identify the inspiration for "Avenue Q."  Most of the characters in the show are puppets, and the set depicts several tenements on a rundown street in New York City.  Several characters are parodies of "Sesame Street" regulars: for example, the roommates Rod and Nicky are based on Bert and Ernie, while Trekkie Monster is based on Cookie Monster.  However, these characters are in their twenties and thirties and face adult problems; despite the fuzzy faces, this is not a children's show.  After a run lasting more than six years and 2,534 performances, the Broadway production of "Avenue Q" ranks in the top 25 longest running shows in Broadway history and continues to have productions run worldwide.  Paperback, 160 p.