From the finish line to immediately following the race

finish line official time 3:09:10 / fergie_lancealot

There are services that will take your photo at the finish line, then sell you the photo from a website. Using such a service allows you to keep good photos of yourself smiling as you cross the finish line.
After finishing, do your stretches, then use ice or spray to ice your muscles. Your next meal should contain sugar and protein.