Ditto paws! There are more different types of seizures.
Grand mal or generalized seizures are when the entire dog's body convulses, and is what people think of when they hear the word "seizure".
Petite mal/focal/partial seizues are much different. In this type of seizure only part of the brain is affected, which can result in some very strange behavior.
Personally I have experienced both types of seizures, and it does sounds as if seizure activity should be considered as an explaination.
This is a great site with everything you could want to know about canine epilepsy. Canine Epilepsy and Dog Seizures Table of Contents - Canine Epilepsy Guardian Angels
Please check out the articles on the different types of seizures, in particular "Partial or Focal Seizures (Petie Mal)."
I highly recommend that you begin a journal for your dog. Record anything out of the norm on a day to day basis. When he does have an episode record everything.
Date, time, symptoms, length of episode, strange behavior earlier in the day, behavior afterwards, weather, and anything else that you can think of!
You may even want to try and record it with a cam corder so that your vet can actually see what is happening.
Last thing! If you do not see any improvement or find any answers, you may want to get a second opinion and possibly seek out the help of a specialist.