Are there any existing sources for topics or projects which are:
- Suitable for first and second year undergraduates taking introductory math classes (possibly with some prompting or a couple pages of background to point in the right direction).
- Have sufficient low-hanging fruit that a group of 3-4 students will typically discover something meaningful within 3 or so hours of group work.
- Are open ended enough that a group won't run out of things to find.
The second condition seems to be the tricky one; with more time, students can spend a long time messing around with data collection and hunting for patterns and finding some false starts. This is a relatively short program (45 min a week for 4 weeks), so we need things which are a bit more directed.