Those with a Google homepage may have noticed a section called "Wei-Hwa's Puzzle Challenges." The first came out on Friday:
Using the numbers 3, 3, 8, 8 (in any order), make a mathematical expression that equals 24. You can use only addition, subtraction, multiplication, and division (and parentheses), but in any order you wish. Note that you have to use all four numbers; otherwise 3 times 8 would be valid -- and that wouldn't be much of a puzzle, would it? Stumped? Look in comments for the solution.