how many can you play?
Bar songs? Couldn't give you a number. Popular music and jazz standards are fairly easy to memorize. I mean, we're not talking about memorizing Stravinsky here or anything.
I can read music just fine, but I'm not very good at sightreading (as in playing a piece of music having never seen it before) on piano. Saxophone, flute and clarinet I can sightread proficiently, and I'm passable on violin and viola. I don't know if that's what varus really meant when he said "site reading [sic]," and if he is a proficient sightreader on piano, I'm somewhat jealous. If he just meant playing from sheetmusic, I'm not. Though, I'm sure I could sightread bar music.
Of course, now I'm imagining someone sitting down at a Steinway and pulling out one of these: