Coffee shop Internet problem

So, I have this thing where I hate staying inside the house for days at a time while I work and do my little thing all in a small space. I need to get OUT. I need to have the hubbub of people around me while I do my thing. (Note, not the hubbub of people who want me to pay attention to them. Just the hubbub of people who are doing their own thing while I do mine.) But something odd has happened to me two days in a row.

I get to Aroma, sit down with my coffee, boot into Ubuntu 8.10 and start to work. After a couple of hours, my Internet just dies. I try to log back into the Wireless connection, check my ip address. Request a new one. Fiddle and fuss, but nothing. I can ping the coffee shop's Internet gateway, but I can't see anything on the other side of it.

Logically, I thought that there was maybe a time limit on how long you can use the Internet connection here, that it recognized my MAC address or something and blocked me for the rest of the day. I dunno. But, on a lark, today I tried to log back into the network on the Windows partition. And it worked. Not only that, but it never died again.

Anyone got any ideas what's happening here?

Wireless connection from the command line

If ever you find yourself stuck with a *Nix box that won't boot into any kind of comfy graphical interface, and you need to connect to a wireless internet connection so that you can look stuff up and maybe solve your problem, here's a helpful tip:

There is a wireless networking utility very much like ifconfig called iwconfig. When you have a chance (and preferably before you really need it) check out the man page for it. Here are some quick and dirty instructions, in case you are desperate right now.

To find out what wireless networks are available to you, type
iwconfig wlan0 scan (see comments)
iwlist wlan0 scan

To attach to an open, non-encrypted network, type
iwconfig wlan0 essid netname
where netname is the essid of the network you want to connect to.

If you only have encrypted networks available, you might be in a bit more trouble. I haven't actually managed to get that working at all yet, though theoretically, it should work something like this:
iwconfig wlan0 key s:password
iwconfig wlan0 essid netname
where password is your password and netname is the essid of the network you want. The s: means that the password is in string format. If you know the hex version of your password, then instead of saying s:password you'd just type in the hex of the password like this:
iwconfig wlan0 key 0123-4567-89

Good luck getting your GUI fixed!