Words/Phrases I run into

[Shinobi Chirlind-Byouko]

Hello folks,
Every now and then when I do lyrics or shows, I run into phrases I just don't get.
Some time ago, it was 「そうこなくちゃ！」　
I googled and found "Now you're talking!" So far so good.

Now here's another one, mind helping me out?

ここぞって時 or ここぞという時
Ex.
「プレゼント渡そうと思ったのに…。
せっかく描いた絵だもん。ここぞって時に先生に渡して、びっくりさせるんだ。」

Thanks!!

EDIT: Thanks, RaintreeLeaf!!

[raintree_leaf]

at a critical moment // at the psychological moment

[mopuis]

ここぞって時 or ここだという時 can be interpreted in several ways :
a very good opportunity to do something
a moment when your choice or action does matters

So, I would translate 「ここぞって時に先生に渡して、びっくりさせるんだ。」
like this : When I think "THIS is the time! ", I will give it to my teacher
and surprise him.

[Shinobi Chirlind-Byouko]

Thanks to all for the responses!
I hope I'm not stretching it too far by saying
"I'll wait for just the right moment to surprise him (my teacher) with this."

Here's a very common one, especially in songs: 時を越えて
Exactly what does this mean? I've seen it as "time passes" (which I really doubt), "timeless" (sounds nice, but I wonder...), but I'm never really sure. I'll look for some particularly troublesome examples for me.

[AzureDark]

Kaitou St. Tail OP!

Well, that'd be "to bypass time" which normally means eternal... at least that's what I would normally put down as.