Writers, comedians, cartoonists, advertisers, speakers of all kinds have been using irony for years - it's a fantastic way to create humor without being directly hurtful - while still communicating a point for your audience. Irony plays a huge role in the success of the Far Side, Calvin & Hobbes, Dilbert and Doonesbury. Shows such as Seinfeld, Fraser, and Community all use irony as their main source of humor.
Today, irony runs rampant on Facebook (TIP: FB can be a good place to test your ironic laugh lines before getting in front of an audience).
Pinning down the definition of irony isn't easy. The definition above is accurate, but its application is so broad, training people to use it is a very specific exercise. For your individual speech, you need to carefully look for moments irony will add to your message, or even lighten your message.
You can't force irony - it has to come naturally out of the scenario you're describing. Below are some quick examples of identifying irony from my own life:
A. I have a blog called RichAnyway - A Blog About Life With No Excuses. So far, I haven't done much with it, and every time I start a post, I have to actively avoid making excuses for not blogging enough. Sad, but true. And Ironic.
B. I just put my book Go Ahead & Laugh on Amazon. To do so, I had to recreate the files, and redesign the cover. Where's the irony? It says "compiled and Edited by Rich Hopkins" - a typo in the very line identifying me as the editor. Sigh. I've decided NOT to change it, and instead call it a "bonus humor tip"!
C. As parent, I continually find myself the victim of irony - such as telling my kids to pick up after themselves, and then being called out for leaving dishes, cans, or clothes laying around - usually because I have to get up in a hurry to make sure THEY are doing what they are supposed to. They call me out, and it's irony on two different levels, both what I did and WHY I did what I did.
The use of irony, as with any humor, carries risk. Pointing irony back at yourself is the first and best option, using secondary characters such as your family and friends is a close second. Using irony to poke fun at political or religious situations is dangerous, and even poking fun at the competition can put you in a bad light. Know your audience, with this, and ANY type of humor.
First, find the moments you talk about yourself, and see if you could be seen playing the fool without losing credibility.
Second, find the serious spots, and look at the situation with the eyes of an outsider - it may be serious up close (such as your truck bursting into flames), but bystanders may have a different spin on it.
Third - get a coach who edits for content, not just grammar - a creative coach. I work with my clients on discovering the humor in their speeches everyday, humor they overlook by being too close to their material.
Irony is the first of several methods I'll look at over the next couple of weeks. Play with it, practice it, and USE it. It's a great way to Speak...& Deliver!
Bonus Tip - Sarcasm is similar, but different. It can use irony, but isn't always pure irony. Consider it a slightly evil twin brother. Check out "Speaking of Sarcasm" for more.