It's just like a regular party only with the element... of surprise! Just make sure your guest of honor has a good sense of humor and will appreciate being caught off guard.
To begin, select a date for the party. Then enlist someone to plan a "fake" activity with the guest of honor. This
not only throws them off the scent, but you'll be sure that the guest of honor will be available that day to have their surprise... sprung.
When sending out invitations, give clear instructions that it's a SURPRISE. Also, to ensure that everyone is in attendance before the big moment, schedule the start of the party at least 30 minutes before the guest of honor's scheduled arrival.
For surprise party invitation wording, make it fun or personalize it:
There's a birthday Party and you're invited to show
But don't tell Tom because he doesn't know!
So if you can make it
here's a word to the wise
Make sure you come early
because it's a surprise!
Also designate a dress code. If your guest of honor will be in jeans and sneakers that day, avoid any embarrassment by making sure guests don't arrive in fancy party clothes.
For the party menu, forget any ideas about what your guests might like at the party - center it solidly around food, drinks and activities the guest of honor will really enjoy!
If it's a milestone birthday, consider scheduling a party toast along with a "This Is Your Life" presentation featuring a scrapbook of memorable family photos. Finally, don't forget to have the camera ready -- for the big moment when the honoree arrives and everyone shouts.... SURPRISE!
On the Web, check out more party ideas for surprise birthdays, or baby showers with tips & advice on planning a great celebration for a friend or loved one with the extra
added element of a good surprise...
More about surprise parties around the Web:
Surprise Party - Adult Party Ideas - Check out visitor-submitted ideas for birthday surprise parties categorized by age from 18 to 80.
How to Plan a Surprise Party - Here's a first-person account of a surprise party successfully pulled-off, and an extra good tip if you plan to invite young guests - don't tell
the kids until absolutely necessary!
Surprise Party Ideas from Evite - Check out tips, suggestions and helpful hints on party planning and decorations, along with food & drink menus, a music list and of course free e-invitations to send.
also see -> Birthday Party Ideas | Retirement Party Ideas
Baby Shower Ideas