When I fall into a creative rut and find myself playing similar bass lines over & over again, I take some time to listen to music with bass parts that are completely different from what I normally play. Example: my band is a jam-influenced indie rock band, so for inspiration I may listen to Latin music or old school R&B for more active, hook-driven bass parts to help me get away from the standard root-octave-5th patterns I'm most prone to playing.
Another good exercise is to practice playing scales in thirds, both ascending and descending. It creates new ideas and gets you away from the kind of patterns you mentioned above.