Minify your CSS by removing all the unnecessary characters.
Minify your JS by removing all the unnecessary characters.
Get the gravatar.com globally recognized avatar for any email.
Check if the URL is banned and marked as safe/unsafe by Google.
Make sure your passwords are good enough.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Get approximate IP details.
Get all the HTTP headers that an URL returns for a typical GET request.