Looks like Helvetica Invisible

Or maybe even UltraInvisible…
Unless you’re talking about the American Typewriter (Light) font on EF’s fonts4ever site.
Cheers,
Jörg

You mean Today by Volker Küster? Maybe have a look at FF Yoga Sans, a “contemporary alternative to Gill Sans”.
http://www.fontshop.com/fontlist/super_families/ff_yoga/

More in this list: http://www.fontshop.com/fontlist/alternatives/gill_sans/

Hm. I do like Yoga serif. But recommending Yoga Sans as alternative to Today is like suggesting a truck to someone who asked for a racing car ...
A shame that Today's character set has not been extended yet.

Cronos should work, and Adobe's EULA permits adding glyphs, so even if it doesn't have the characters you need, there's a way out.

I've extended two weights of Today Sans into a Pro character set a few years back, and sent the results to E+F, but they did not do anything with it, as far as I know.

Agenda, from Font Bureau, or Bliss, from Jeremy Tankard, might be suitable substitutes.

Agenda and Bliss are nice alternatives to Gill Sans, but none of these is that similar to Today Sans, IMO.

Obviously these are all humanist sans, so there are more similarities than differences perhaps. I guess it really just depends on what aspects of Today the o.p. is looking for.

Freight Sans has some similarities with Today Sans, I think… I'd never noticed it, but myfonts pointed that out. Alright Sans, too.