The Sims 2 Tips

Vanilla Milkshake
You can get a milkshake instead of regular milk from the cows. Do do this, go up to a cow. It should say "milk", "tip" or "give gift". Select Tip. Immediatly after tipping, select Milk. Voila! You have a vanilla milkshake!

Note: you can do this with both cows.