I use Google Maps a lot to investigate a place I'm going to or to get direction there. I've noticed that on Saturday mornings Google Maps often fails but when it doesn't it just runs real slow and I get this message:
Still loading... Slow? Use the troubleshooting guide or basic HTML.
My theory is that everyone is using Google Maps to find directions before or while going out on a Saturday and this is overloading their maps servers. When are you most likely going to need directions? When you go somewhere you haven't been to in a while or ever. That's not going to happen during the week when you're going to and from work, that's going to happen on the weekend when you have the time to adventure off the beaten path. So my guess is that the requests to the mapping service peaks over the weekend.