Fun to watch Jon Stewart get out of the way and just let him roll with it. Some good, heartfelt talk about his early days doing standup, the importance of "leaving a tip" onstage, and how silence is when you know you've REALLY got a crowd.
And here's From Presentation Skills to Masterful Performance: 12 Tips from Billy Crystal by Victoria Labalme.
Variety of Tone - notice the variety in his speaking tone, which ranges from warmth to humor to respect for nominees. In other words, he is not speaking in "one color"...Use the full spectrum of what you have. The audience craves variety. Important note: Keep in mind that tonal shifts must always come from the "inside out." If you force the shift, you will sound inauthentic.