If you're looking for 2hr single tracks you'll be running into looped tracks or very long albums. For a group setting, pizza's reference to boiler room sessions is spot on. Those are dope and pretty safe bets.
I personally, will blast some Glenn Gould Bach Variations [1], or some Sleep Dopesmoker [2] when I really want a long collection of hypnotic sounds to lull me into flow.
[1]: https://www.youtube.com/watch?v=Ah392lnFHxM
[2]: https://www.youtube.com/watch?v=hIw7oeZKpZc (<== will make you feel like an invading Mongol horde)