Easy way to recreate this wavy shape?

I'd bet a number of your fonts have that shape for a tilde, but drawing with the pen tool probably is the best way.
That shape should have 4 points, one on each end and one on each of the sides at the middle. After you use the pen tool you would probably also use the direct select tool and the possible the convert anchor point tool to refine the curves.

Maybe watch this tutorial video:
http://library.creativecow.net/articles/rosati_vincent/ai_helix_2/video-tut...
It shows some techniques for refining paths.

Vince

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