How I Met Your Mother 4x21: The Three Days Rule
| Serie | How I Met Your Mother |
| Staffel | 4 |
| Folge | 21 |
| Länge | 30 Minuten |
| Genres | Comedy, Romance |
| Erstausstrahlung | 13.02.2010 |
| Autoren | Greg Malins |
| Regisseur | Pamela Fryman |
Die Schauspieler der Episode
| Schauspieler | Rolle |
|---|---|
| Josh Radnor | Ted Mosby |
| Jason Segel | Marshall Eriksen |
| Cobie Smulders | Robin Scherbatsky |
| Neil Patrick Harris | Barney Stinson |
| Alyson Hannigan | Lily Aldrin (credit only) |
| Rebecca Budig | Holli |
| Kevin Michael Richardson | Stan |
| Bob Saget | Narrator (voice) (uncredited) |