1. Don’t send invites too early – the earlier you send the invites, the more time there is to leak the existence of the party. Send them about a week in advance so people can block it out.

2. Don’t give too many details – start out with a Save the Date. Less details means less to leak. They don’t need to know where it is … yet.

3. Make the invite private – if you’re using Facebook or some such, remember to make it private so it doesn’t show up on feeds. “40 of your friends are attending your surprise party!” is not a good feed item for the target to receive.

4. Get trusted help – figure out what tasks you need done and assign them to volunteers. For example, getting a cake, getting decorations, getting snacks, putting up the decorations. The less people involved, the better.

5. Set the time earlier than you need to – no matter how much you tell people that they have to be on time or they’ll ruin the surprise, people will still be late. Up to an hour late.

6. Create a distraction – obviously, you need to make some kind of plausible distraction event for the target so they don’t suspect. A dinner for two works well. Acting drunk may also yield good results.

7. Get a liason – to communicate with and inform when the target is arriving. Text messages work really well for this.

8. Keep them busy – you gotta keep the target busy on the day, especially when you need to text your liason. Suggest that they drive. Or intoxicate them. But not both.

9. Make sure the surprise party can breathe – a lot of people crammed in a small space can get uncomfortable. Dead surprisers are even more surprising, but not as fun.

10. Take video

As witnessed in the surprise party I put together for Coley with the help of Willo, Min Jung, Jason, Cindy, Marianne and the 40 people that came. The video from the outside:

Coley Supplies! from Kevin Cheng on Vimeo.

And the video from the inside, including the false alarm/beta-test:

SURPRISE! from blissforkface on Vimeo.

Photos of Coley’s birthday by Brian, Bliss, Tantek, Marianne, Cindy and me: