1. The roundest knight at King Arthur's round table was Sir Cumference... He acquired his size from too much pi.

2. I thought I saw an eye doctor on an Alaskan island, but it turned out to be an optical Aleutian. 

3. She was only a whiskey maker, but he loved her still. 

4. A rubber band pistol was confiscated from algebra class, because it was a weapon of math disruption.   

5. No matter how much you push the envelope, it'll still be stationery.