I got the 770 about two years ago. It was a fun while it lasted, but I eventually got an iPhone.

So I have an old 770 Internet Tablet, and I use my iPhone much more frequently as an internet tablet. If I sold the 770, I would get maybe 50 bucks, right?

So what practical use could the 770 serve for me? I'm interested in hacking it, making it into a clock or something fun.

Do that! Mine now hangs in the kitchen serving as a clock, music player, and RSS news reader.

Frontend for a Carputer?
Wireless remote for a media system?

keep it in mint condition and sell it in 20 years as a piece of fascinating history?

some options:
-wireless remote to pc (vnc / rdesktop)
-bedside clock/alarm
-gift? (children will love it !)

...will think of other usages...

Best! eBookreader! Ever!

(cheapest too)

How do you power it, do you have charger constantly attached? Does it charge itself as needed? I was thinking about switching charger off and on when low on battery via some interface (usb in host mode perhaps) but I guess it is just too complex and not really needed (to save power).

The charger is attached constantly. Sometimes I pull it to let the battery discharge. But I don't worry too much about the battery. My 770 has had its time as a mobile device.

Sometimes I also pull it out for reading an ebook. As Karel already noted, the 770 is the best ebook-reader ever. I fully agree!

Now that the touchscreen on mine has gone flaky, its being used primarily as a digital photo frame - its got a much better/higher res screen than darned near every dedicated frame I've seen.

it's a good movie player for the kids while you wait at the hospital/clinic or on a road trip.

add some games like "frozen bubbles" and it will keep them quiet.

small liteweight webserver