I've noticed that running
apt-get update recently has resulted in quite a few ppa's returning "403 Forbidden". In and effort to clean them up I had a look:
W: Failed to fetch http://ppa.launchpad.net/gnome3-team/gnome3/ubuntu/dists/raring/main/binary-amd64/Packages 403 Forbidden
W: Failed to fetch http://ppa.launchpad.net/gnome3-team/gnome3/ubuntu/dists/raring/main/binary-i386/Packages 403 Forbidden
E: Some index files failed to download. They have been ignored, or old ones used instead.
The strange things is, if I copy these URLs into my browser I can access the files just fine. Why would apt-get report "403 Forbidden" if they're still accessible? I tried re-adding the ppa through
add-apt-repository which downloads the signing key again, and it still reported "403 Forbidden".