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 all possible details about an SSL certificate.
Get all possible details about a domain name.
Ping a website, server or port..
Use the Google translator API to generate text to speech audio.
Get & verify the meta tags of any website.
Get all the HTTP headers that an URL returns for a typical GET request.
Get approximate IP details.