Take an IP and try to look for the domain/host associated with it.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Get approximate IP details.
Get all possible details about a domain name.
Ping a website, server or port..
Make sure your passwords are good enough.
Convert your HEXA color format to RGB format.
Use the Google translator API to generate text to speech audio.
Get the gravatar.com globally recognized avatar for any email.