Hey guys,
Yes, both schools certainly have several CUP programs in place. I'm not sure about BIG - this is certainly a Tucson thing and is probably offered at Phoenix as well, but I haven't participated in it personally and it may be more a part of the MPH program (many students do a combined degree, and most still do it in only four years).
CUP is awesome. I'm not actually sure how many programs are now in place at Phoenix, but it seems like new ones are popping up all the time. We have many that are ongoing, such as the most-popular Wesley Center (student-run clinic), as well as Planned Parenthood, TarWars (anti-tobacco education), a program tutoring middle school students, another teaching health and nutrition to high school students, a health-mobile health-on-wheels program, a teen pregnancy center program, CPR training and teaching, etc. (sorry, I participate heavily in a few and don't even know the names of others!) - these are only the ones I can remember off the top of my head but there are others. There are also many CUP opportunities that pop up during the year and take place once or twice annually, including kids health fairs, special events through Wesley Center, and some other random ones (like this past year we participated in the "Ask a Med Student" event at Body Worlds in the AZ Science Center, which was a ton of fun). Additionally, if you think of a good way to serve the community that isn't currently being done, you can always start a CUP program yourself! CUP is great because it allows you to practice the skills you are learning in school (especially Doctoring and LCE) while also volunteering and giving back to the community (and add to your CV!). You can also build up enough CUP credit to receive one or two weeks elective credit in MS4 year and possibly graduate with a Distinction in Community Service.
I hope this helps!