I read somewhere that after an intense workout you should eat to replace glycogen stores within the first half hour...

That kinda how we work anyways...

During a race (Hr elevated and sitting around lactate threshold) that takes more than an hour I eat (as in cram a whole fruit bar into my mouth) or suck down a "gu" at one hour and then every half hour.

An endurance ride (up to 4 hours) I start eating about 1 1/2 hours in (one fruit bar) and eat another every 30-45 minutes.

For a time trial (HR elevated above lactate threshoold for approx 40mins) I eat solid food no closer than 1 1/2 hours before my start, have a gu and a caffiene drink at the start line and then try and eat a couple of biscuits as soon as I can after I finish.

When I am supporting my lads for/after races (rr or tt), I have a chocolate milk or a recovery drink ready, or fruit like a banana or oranges and bickies. Thats for the first half hour. That will usually tide them over til we get home and they can doze while I get them something more filling and sustaining.