Here's a little something I threw together a few weeks ago. The following is a bunch of number-and-letter associations, with a phrase hidden within. It's actually real easy once you know what to look for. That is, unless you fucked off in all your math classes, then you might never get it.
15H 42X 21A 27O 14P 37I 33E 94P 03F 10F
18U 04P 19Y 10A 23O 16B 52Z 43U 14D 27I
29C 36H 38F 28P 54E 02A 12C 40O 17N 06D
12E 33B 53R 07E 49R 05A 36U 25T 38E 11D
24I 13T 32S 41H 15O 08R 19I 23S 16A 09P
36B 28U 37Y 18E 43O 45C 14X 34A 05U 27S
07N 48P 19E 30O 28N 15D 29E 06Y 27V 31D
35I 02T 25E 12A 44M 53O 55F 21J 34L 42E
49K 33R 46A 15G 21E 36E 07G 27R 13E 41T
52E 17L 08B 23A 25R 32T 45R 41I 10A 05D
Anyway, give it a try. It's not a question of if, but when, somebody here gets it, because I know there are those here who cannot resist something like this. If you think you've got the answer, post it.
Feel free to make up new ones with slightly different rules. You might even try hiding two or three messages in the same block of text.