I "discovered" a scale about a month ago when playing with the Ionian b2 (which is now, by the way, part of my regular improvising vocabulary). At the time I thought it was just a curiosity but I liked the sound and since then I've seen it pop up in a few other places.

I was surprised when I saw Adrian Galysh describe it as "the scale that'll change your life":

and even more surprised when I heard something very similar from Jack Zucker, saying he took it from Joe Pass (he actually plays one extra note in here, but it's a closely related sound):

Finally, here's an explanation of the scale on piano:

The scale is spelled 1 #2 3 #5 b7, which might not look like much. In Arpeggio and Scale Resources it's listed as the "Phrygian Pentatonic b4", which doesn't suggest anything very exciting. I discovered it because its fingerings look just like those of the Major Pentatonic with a flattened 6, or the Minor Pentatonic with a flattened root (which sounds a bit weirder but is very easy to find).

One thing to notice is that it's a subset of the Altered Scale that jazz guitarists like so much: 1 b2 b3 (=#2) b4 (=3) b5 b6 (=#5) b7, with the b2 and b5 taken out. So a first use of it is just as a sub for that scale. Personally I always found the Altered Scale too cluttered with different kinds of dissonance for my taste, and this one suits my style much better. I can always add the b2 or b5 or both when I feel like hearing them.

Next we can look at its modes. The Major Pentatonic b6 is, in fact, a lovely sound over major 7 chords; it's a subset of the Harmonic Major, which is a scale that everyone ought to know, and this is a good step towards learning it. It's also a subset of Latangi, an Ionian b2 mode that has a similar kind of sound but is a little more angular thanks to its #4.

The other three modes all sound great too. Dorian b5 Pentatonic is bluesy but also works well over minor or half-diminished chords. Myxolydian Pentatonic b2 suggests a major 7 sound to my ears, bringing to mind the Ionian b2 itself. Altered Pentatonic III also works well over major 7s and has a sound that's reminiscent -- for good reasons -- of Coltrane Changes.

Check out this interesting and easy-to-learn scale and see what you think.

[UPDATE: Spectral Analysis of Scales is now out, and completely free to download. The 7-spectrum of this pentatonic contains Melodic Minor and Neapolitan as well as Harmonic Major and a bunch of very exotic scales, so (as always) there's a lot more to explore here.]