Here are a list of useful and some times interesting commands you can type into the URL bar. Some of them seem quite handy and some others like the about:internets are just a bit of fun. So just try them out.
about:cache
about:dns
about:histograms
about:objects
about:memory
about:plugins
about:stats
about:network
about:version
about:internets
about:crash - no worries, just shows the sad face when a tab crashes.
chrome-resource://about/
chrome-resource://favicon/
chrome-resource://inspector/inspector.html
haha: chrome-resource://inspector/
chrome-resource://chromewebdata/ (empty)
chrome-resource://new-tab/
chrome-resource://thumb/
view-source:chrome-resource://about/stats
view-source:[any url]
chrome-resource://about/[any about target]
view-cache: