Peculiar AND “Ha Ha”

For a number of years, up until somewhere in my late twenties, I would, on occasion, get an odd sensation in my legs.
It generally happened if I was especially tired, but it would also strike at random.
The only way I could ever think to describe it was to say, “My legs feel funny.”
And by “funny,” I meant both ways:  funny peculiar and funny ha ha.
See, it was an peculiar sensation that would actually cause me to laugh kind of uncontrollably.
I don’t mean non-stop, maniacal laughter when I say “uncontrollably.”  Rather, just that I wasn’t able to control it:  the feeling would kind of surge, and it would make me laugh, whether I wished to laugh or not.
The worst part was that the harder I laughed, the funnier my legs would feel, and the more I would laugh.
I don’t really remember a time in my life when I didn’t get the feeling, and I’m honestly not certain when it stopped, but I realized one day, years ago, that I couldn’t remember the last time my legs felt funny.
Over the past few days, however, as I’ve been wearing myself out with my workout routine, I’ve found that the funny feeling has returned with a vengeance.
It’s no longer limiting itself to my legs:  my entire body feels funny.
(I am currently engaging in a Muttley laugh in response to a surge of funniness throughout my body as I type this.)
I really don’t understand why this peculiar feeling elicits laughter.  I mean, it isn’t a tickling feelings.  It’s more like a feeling of total exhaustion, and a loss of strength (sometimes, when it was limited to my legs, I would actually go completely weak at the knees, my legs would buckle, and boom, Jon fall down).
It’s kind of like that feeling you get when you’re just really settled into a chair or something, and you don’t feel like you have the strength to get up, yet you know you do.  If you really work at it, you can make yourself stand up, but until you can muster up that surge of energy, you feel as though you don’t have any strength at all.
(Pause for more laughter.)
*Cough*
*Snort*
Sorry, I went full-on Lewis Skolnick there for a second.
So…anyone out there have any thoughts on potential causes?  Simple exhaustion?  Endorphins?  Jacked-up nervous system?
No matter what the cause, all I can say is that my body is funny.