Pretty much what the title says: my Apple Wireless Keyboard connects to an iPad perfectly, but not to my MacBook Pro. I used the usual process of switching the keyboard off, then holding the power button until the light flashes. Just in case it matters, I have reset the NVRAM and SMC, to no avail. Interestingly, the Magic Trackpad 1 connects flawlessly to my Mac, however.
Note that I have not (tried to) use the keyboard with any other devices, and that I forgot the device on the iPad.