Turning 21 is a milestone for which friends and family often gather to celebrate their loved one. The most memorable part of the birthday party could well be the speeches. Anecdotal and humorous, they should share and reflect upon the delightful and distinctive characteristics of the birthday celebrant. Make sure that the speeches are done when all the guests are assembled for that purpose.
A 21st birthday speech should be engaging and make the audience laugh. Include some humorous anecdotes of things he did as a child and share some embarrassing stories from the school years.
The audience will relax and warm to you and the guest of honour will likely take the ribbing in stride. But don't include overtly crude or inappropriate stories that the birthday person has told you in confidence, no matter how funny they are.
Reflect on the birthday person's accomplishments. Select a few achievements that she is proud of and worked hard for. Praise the qualities and personality traits that you find most endearing. If you've spent four minutes making fun of the person, spend at least two minutes building her up again and share what she means to you personally.
Pictures and Videos
If you can obtain an appropriate projector, show some photos of the birthday person. You can use them in your speech for comedic effect by synchronising your speech to a slide-show or contrasting your words of praise with pictures exemplifying the opposite.
Another idea is to show clips of funny home videos of childhood scenes, to offer glimpses into the birthday person's history that few people would have seen. Be careful to not have videos run for too long; perhaps get help from a pro in editing the clips into a brief clever show, perhaps with a comedic title for each vignette.
An important point to stress with 21st birthday speeches is timing. A speech that will be well received and enjoyed by everyone will not be too long. Don't test the audience's patience by talking for over ten minutes. Prepare and practice your speech beforehand and either have it written word for word, or have some notes to keep you on track. A funny short speech is much better than one that overstays its welcome.