These were all problems from the SF math circle math festival.  I ran a problem solving booth involving problems that had nice solutions if you could translate the problem to binary.  I also introduced the students to other counting systems as well.  Try some out for yourself!

Pascals Predicament

For Fibonacci's Sake

Fun with Functions

Decipher the Cypher

Floors on floors on floors...

Too many twos (Julia Robinson Math Festival)