Steven Wright is a really funny standup and is a good example of how not to win a Toastmasters Humorous Speech Contest. He’s very deadpan, lethargic, and relies on killer one-liners:

• “I’ve been getting into astronomy so I installed a skylight. The people who live above me are furious.”
  
• “It’s a small world, but I wouldn’t want to paint it.”
• “Curiosity killed the cat, but for a while I was a suspect.”
• “I went to a store that had a sign that said “Open 24 Hours” and it was closed…I asked the manager ‘Why are you closing? It says you’re open 24 hours.’ He said ‘Not in a row.’”
• “If it’s a penny for your thoughts, and you put your two cents in, someone’s making a penny.”
• “I finally got around to reading the dictionary. Turns out the zebra did it.”

Your humorous speech contest entry is a humorous speech. That sounds obvious but it’s not. To rephrase it, your humorous speech is not stand up comedy. You can’t get up and tell a bunch of unconnected jokes and expect to win out too far. You need to have the standard opening, body, and conclusion of a speech, that just happens to have funny material in it.

If you look at the judges’ evaluation form, you get a sense of this:

Also recall all the points you get for vocal variety, moving around, and so on in the humorous contest judging section.

But it’s more than just that. Most judges I know have knee-jerk reaction that a humorous speech is not standup and will knee-jerk vote down anyone that they think is a standup routine. A standup can not move around at all and be totally monotone like Steven Wright because he’s not judged by the same criteria Toastmasters are come contest-time.

That said, you need elements of standup - namely the people laughing when you tell jokes.