Something I've done that doesn't require much technical knowledge is to change the "AutoCorrect" options in Outlook on someone else's computer so when they typed a regular everyday word it would correct it to something completely different. I had a co-worker who wouldn't buy anything without a coupon, so I changed his AutoCorrect to type "I love coupons!!" everytime he typed "the". It was quite funny to watch... and read... since he didn't notice it for a couple emails!