Gap is running a commercial with a shaggy-haired dude dressed in
denim, of course, gettin his groove on to a funky little tune with
these lyrics...

What makes ya feel like doing stuff like that?
(I dunno but it sure feels good)

This great old song is "Stuff Like That," which was originally
recorded in 1978 by Quincy Jones, with Ashford and Simpson.

STUFF LIKE THAT

Walked in the joint
They were lined up back to back
Anything you can name, no shame,
uhn, uh
An' stuff like that

Do it - do it
Do it - do it

(Chorus)
What makes you feel like doin' stuff like that?
What makes you feel like doin' stuff like that?

Before my eyes
Was the promise of paradise
Is she real, can she feel
Is she a dream? If ya know what I mean
'Cause she was built out of
Stuff like that

Stuff...Like That (do it - do it) *4 x's

I knew I was captured
By the rhythm of the magic flute
Pulling and urging me
To taste the forbidden fruit
Tho' I felt naive
I did not want to leave
Fever was in the air
All of a sudden, I didn't care
No reason why, I just had to testify...

Leo's Lyrics: Stuff Like That
http://www.leoslyrics.com/listlyrics.php?sid=A%21v%CE%93G%E6%B9

You can purchase this song, along with many other Quincy Jones
classics, on the album "Quincy Jones: Greatest Hits."

CDNow - Quincy Jones: Greatest Hits
http://cdnow.com/cgi-bin/mserver/SID=814955096/pagename=/RP/CDN/FIND/album.html/ArtistID=JONES*QUINCY/ITEMID=367693

Here you can find more information about the song, in a reminiscence
by Quincy Jones himself:

Warner Brothers Records: Quincy Jones
http://www.wbr.com/quincyjones/jookjoint/stuff.html

My Google search strategy:

"stuff like that" + "ashford and simpson"
://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=%22stuff+like+that%22+%22ashford+and+simpson

If anything in my answer needs explaining, or if a link is not
functional, please do not hesitate to ask for clarification.

Thanks for asking about a wonderful song!

Best wishes,
pinkfreud

Perfect answer.  Note: This question WOULD have been priced at $4, but
Google is now using radio buttons to force questions into silly price
categories.