Hundreds of people give blood sweat and tears, in the name of charity.
Well maybe just a lot of sweat.
Saturday is the CASA 27th Annual Spearfish Canyon Half Marathon and 5K race.
The event drew more than 400 people all giving it their best to raise money for the cause.
CASA stands for Court Appointed Special Advocates, who train volunteers to become powerful voices in court cases involving child abuse and neglect.
Event organizer Kate Kelly says this is their biggest fundraiser of the year, "We're thrilled with how many people want to participate in this... it's just great all around."
Kelly says she hopes to raise more than $25,000 from the races.