I'm just gonna pretend the misspelling was intentional :)

"You should of done something"

"This has no affect on me"

They're everywhere.

I recently heard someone say "cow tailed" instead of "kowtowed"

After cleaning up some spilled toner, someone put a very indignant notice under the photocopier:

"It would be who of you to be cautious openening a new toner cartridge."