In reply to Hjonesy: Some other ideas...
Have a game of consequences, the kid's game on bits of paper that you have to roll up as you go along and then all read out at the end. Alter the storyline to include people, projects and things from the company.
Get a pea shooter. First to get a pea into cup placed at a strategic distance away wins a prize; a tin of marrowfat peas.
Get a box of matches and some cards and have a game of Irish Brag. Give everyone an equal number of matches for betting, then deal everyone a card face down. You all have to take the card and hold it to your forehead, so you can see everyone else's card but not your own. You then have to bet matches on your card (sounds complicated, but can be a hoot).
T.