runathon
/ˈrʌnəθɒn/(also run-a-thon) informal (originally US )
noun
1 Baseball and Cricket. A match in which an unusually high number of runs are scored.
2An event featuring long-distance or protracted running; especially one undertaken in order to raise money for charity.
Origin
1930s; earliest use found in Bakersfield Californian. From run + -athon.