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 ascii and the other way for any string input.
Convert text to octal and the other way for any string input.
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.
Make sure your passwords are good enough.
Get the web-host of a given website.
Parse details from user agent strings.
Check if the URL is banned and marked as safe/unsafe by Google.