For my own part I made many useless creations/hacks.
One of most recent, absolutely simple and useless is a modification of libTorrent 0.12.6.0 local_id, in order it to appear in other torrent clients as "libTorrent 12.12.12.12"
Stupid, isn't it?
But for those who are interested(you really are? :DDDD), it's statically defined in makefiles, to be more specific: in "configure" and "configure.ac" files, as "PEER_NAME" and "PEER_VERSION"...