For Sprints, you could really go on a recovery ride the day after, and be fully recovered by the day after. Olympics are similar, just don't go for a run the day after, maybe two.
Half Ironmans are a bit of a different story, you probably have at least a week of easy to medium swimming and cycling, running can come a week to a week and a half afterward, but even then, not a fast long run.
I have heard the Ironman recovery period can be up to four weeks, but that depends on everyithing from your age, and what you ate, to your own personal physiologic variables.