MySQL might be the world's most popular open source database, but it isn't the easiest thing to download. I'm trying to get 4.0 on my server, so I've got the download page up locally trying to get the url to give to wget.
They don't want to give you the url so I ended up having to look at the html source and find the ftp server. It's a pain in the ass, especially considering that I'm not going to be the only one wanting to download it to a remote location.
Movable Type is also a pain in this way too. If you're letting people download a server application, give the full url for people like me, it makes our lives easier