I've always needed a tool which can gather every possible information about particular website, eg.: WHOIS, DNS hosts, and even opened ports on each host.
I was always wondering, what was the weather exactly one year ago, with climatevo.com it is (or soon be) possible.
MD5, and other hashes like SHA1, SHA256 cannot be decrypted because this algorythms are lossy. So what we can do?
Hidebox.org is a service which can reduce the amount of "spam" in Your mailbox. I, personally use this site every day.
Spycolor.com is a color conversion tool, that allows You to find and get the details of any color that comes to Your mind. If HSL, HSV, CMYK and RGB tells You anything, You should definetly visit this site.