Convert text to binary and the other way for any string input.
Convert text to hexadecimal and the other way for any string input.
Convert text to decimal and the other way for any string input.
Convert text to octal and the other way for any string input.
Get the gravatar.com globally recognized avatar for any email.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Make sure your passwords are good enough.
Check if the URL is cached or not by Google.
Get details of any file type, such as the mime type or last edit date.
Get the web-host of a given website.