One thing that I have really enjoyed in the past is photo challenges. As a scrapbooker, in the past photos have been my thing but journaling is always tough. The Currently weekly journaling challenge by Kristen is so smart. It's almost like a tiny time capsule for your scrapbook listing all the stuff that you are into. This could easily be incorporated in to monthly collages or project life. If you are feeling really "listy" check out 30 days of lists free month challenge here.
You could certainly use these as a jumping off point for many things. Like use the currently challenge on a monthly basis instead of weekly, on your birthday month try making a list everyday with details about you similar to the 30 days idea, or occasionally include a grocery, to do, or packing list in your scrapbook.
Added 03/13/2013: Found another list of lists for journaling by Kelli. Check it out here!
Thanks for reading!