If you're the serious tinkering type (as opposed to the rest of us who just like to occasionally break things), it's time to check out HTCdev.com. Two-thirds of the site,
announced at the beginning of June

, are now live. The OpenSense SDK gives developers easy access to take advantage of all of the HTC Sense APIs and add-ons. (For example, the tablet pen for the HTC Flyer.)
Then there's HTC's kernel source repository. HTC's been
putting out kernel source

for quite some time, and now it's got a new home.
And, finally, there's the much-anticipated
bootloader unlock web tool

. It's not live yet, but should be later this month as HTC updates the Sensation then the EVO 3D to allow for unlocked bootloaders.