In glendale you can go up Verdugo...or chevy chase to the rose bowl
or even Griffith park and the la bike river trail...
La Tuna is great also...

here are some links to maps of la bike trials and routes as well as a route mapping site..

http://www.labikepaths.com/

http://www.bicyclela.org/maps_main.htm

http://www.bikemetro.com/route/routehome.asp