This will cool you off a little bit, Discovery Channel cameras were rolling as Stig Severinsen went out to set a world record.  The record is for swimming under ice for 250 feet in one breath.  Stig did this recently and the footage is pretty dramatic, he narrates his journey under the ice that seems to last for a long time.  250 feet doesn't sound like much when you walk it but when you swim under ice with a narrow escape route it is quite a challenge.