There aren't many hacks for the Wifi. I've written up what I know about hacking the Wifi here on the wiki
. As for actual hacks, I made a weather forecast display
with my Wifi.
I read somewhere on these forums that it's possible to edit some file in the Wifi's ".kobo" folder to direct the SHOP button to a custom url, such as google or wikipedia, but it's a real pain to navigate webpages on the Wifi.