Make the guest of honor follow a treasure hunt or scavenger hunt, requiring the person to find 30 clues or 30 objects that lead to the party's location. Alternatively, plan a traditional surprise party at home or at a restaurant, and use the number 30 as a theme. Provide the person with a list of 30 activities to complete during the party, or plan food, drinks and activities that incorporate the number.
To plan a treasure hunt, hide 30 notes around the birthday person's home or neighborhood. Each note should lead to the next one's location, with the final clue leading to the party location.
To plan a scavenger hunt, give the person a list of 30 objects to find or 30 locations to visit. Make the last item on the list specific to the party location so the person is guaranteed to end up there at the end of the hunt.
For the party itself, buy 30 different kinds of beer and fill bowls with 30 different snacks or 30 different types of candy. Alternatively, challenge the guest of honor to complete 30 tasks before the party is over. Tasks might include things like "get 30 people to sign this birthday card" or "get 30 hugs."