So last night I had something weird happen. I was able to cast spells without loosing any magicka. The bar would flash but never really change. It lasted for quite a while until I was killed (hour or so). Anyone else experience it? Didn't make me invulnerable but I can't say I didn't enjoy it.

possibly the spell used next to no mana?
you have a high magika?

Hmmm oh no, it went back to normal after I died that first time. I was mostly using firebolt and destruction spells. Too bad, cool while it lasted

If you use Conjuration and Frenzy/calm, you do not need endless Mana or any form of enchantment at all, in fact, you can beat the game on Master NAKED.

Yup, experienced exact that same effect - no mana depletion at all.
Definately a glitch/bug.
It went away when I was forced to reorganize some gear/spells...

Did you just do a certain college of winterhold quest? I got that too, apparently it was due to the "fortify magicka" i had in my active effects. But i had no idea where those effects were from, so im guessing its

In any case it doesnt last forever

Yep, sure did. Guess that explains it, balancing the harmonic energies and such must give the pc a massive reserve or something. Good job to hit before a major obstacle