1- Catch a movie at the historic Castro Theater. Evening shows usually have an organ player before the previews start.
2- Look at the window display at Cliff's Variety Store, it is always a hoot.
3- Check out the rainbow flag and the plaques for Harvey Milk.
4- Go to the LGBT Historical Museum.
5- Come on a weekend for Brunch
6- Come on a Thursday or Friday evening for Happy Hour
7- Ride the streetcar down Market St
8- Go to Dolores Park on a sunny day (not technically in Castro, but close enough)
9- Check out some of the funky and unique locally owned stores
10- Go see some of the historic buildings, such as the Nobby Clark Mansion.