Hulu isn't supposed to play on mobile phones - the service doesn't have the licensing rights for mobile distribution. But about five seconds of settings tweaks in Android 2.2 "Froyo" (only on the Nexus One, for now) will enable Hulu streaming.
The method, as illustrated by Absolutely Android, merely requires you to type "about:debug" into the URL bar, select UAString (which allows you to change the user agent, or the identifying network protocol of your browser) and select "Desktop."
And apparently performance is pretty decent over Wi-Fi - at least according to one user who shared the experiences of a similar exploit on Android Forums. Once you get a decent buffer, the video plays back smoothly and subtitles are legible.
It will be interesting to see if Hulu deems the exploit worth their efforts to thwart, or whether they'll turn a blind eye as they sell a touch more advertising to the 20 dudes with Nexus Ones. [Absolutely Android via DailyTech]
UPDATE: Hulu has already blocked the trick.