Examples of a good student's project with minimal economical knowlege
This question is quite broad, but I'll give 3 ideas I would have liked to do, and is of appropriate difficulty, while in undergrad.


Review a seminal paper - Wikipedia has a list of important publications in economics.  They could write a 10-20 page paper and give a deep analysis of what the authors did and why.  I.e. if there is a derivation they could explain why it is solved that way, if it is the only way, or if there is another way and suggest these alternatives.
Construct a new policy function - Let them argue their intuition in constructing a new policy function (e.g. why do you take log consumption?) and solve for the constrained optimization problem.  They should know how to use the method of Lagrangian optimization, but the courageous student could set theirs up as a Bellman equation.
At my school it was perfectly acceptable for a Bachelor's thesis to do a real world project instead of write a paper.  They could make some kind of event, I had a classmate present on the UN Millennium Development Goals and had a video message from Jeffrey Sachs.  They could find somebody (or a few people) local to come and speak.  Also they may have access to a small budget from their school, or can elicit donations from local restaurants, and can provide food (college students love free food)!