Our lab, 6.5 yrs old, suddenly became weak in his front two legs and nearly collapsed. It seemed like he was dizzy. 5 minutes later he seemed fine again. Does anyone recognize this?

If you are at all concerned about any aspect of your dogs health, I would recommend you have him checked over by your vet.  We cannot give a diagnosis and there may be numerous causes for his condition-best to have him seen to by the professionals, just incase!  Hope he's okay :)

Sounds like Vestibular Syndrome to me. You really need to talk to your vet but with a little luck your dog could well make a complete recovery. One of my Labradors had this at about 10 years old and she led a full life right up to her death at nearly 14.

Regards, John