there are a few things you can do. the principle is one of changing the routine - try playing with new musicians to get some new ideas. Put an ad in your local music shop to find others in the same boat
Buy a new CD and learn something in a new style - if you never have, get a Bob Marley album and work on the sound and feel that Family Man Barrett got - that'll get you miles away from where you are if you've never played Reggae before.
New sounds can help - try new effects, delays, looping - i always find new sounds and ideas that way. Even changing string guage can inspire new ideas. Retuning is another fun one - drop D, tune in 5ths... etc...
try working out parts played on a different instrument - that may send you off on a new tangent.
turn the volume down on the telly and soundtrack whatever you see - that's a great idea I stole from Dale Titus at Bass Player magazine...
and finally - try writing a solo bass piece - trying to think of your bass part as the whole tune can lead you down some unexpected paths...
i hope that helps - let me know how you get on...
steve
http://www.steve-lawson.co.uk http://www.solobassnetwork.org.uk 
