TITLE: Open Problems for Undergraduates
QUESTION [12 upvotes]: Suppose:

I am a 'problem-solver' rather than a 'theory-builder'
I am an undergraduate student
I have a passion for solving mathematical problems
The homework I get is not satisfying (in the sense that the problems are computing-problems rather than problems that require creative thinking), and I get far too little homework


Where can I find interesting problems (that require creative thinking) if I want to have fun solving mathematical problems and to practice problem-solving? Are there lists/books of such problems?

Furthermore, suppose I want to know how it is to do research.

Are there lists of the kind "open problems which can be understood by undergraduates". I guess these open problems should be in the fields of "discrete mathematics/combinatorics" and "graph theory".

I only found: http://dimacs.rutgers.edu/~hochberg/undopen/

REPLY [4 votes]: Richard Guy compiled a list of open problems in combinatorial game theory, available at http://library.msri.org/books/Book29/files/unsolved.pdf . His book "Unsolved problems in number theory" also contains parts which are more combinatorial in nature. In the realm of Davenport's constant there are many open problems, some of which are probably non-trivial but doable.

REPLY [4 votes]: There's a big list of open problems at:
Open Problem Garden
and a smaller list at:
Unsolved Problems and Rewards