People have until midday on Friday to donate to charity and watch what they give double.
The Christmas Challenge 2016 lasts for 72 hours, and during that time any money you give will be worth twice as much.
It’s part of the UK’s biggest online match funding campaign, which means generous donors have pledged to match whatever is given, up to a certain target.
If not enough people donate the match funder won’t give as much either, so charities are urging people to act fast to make sure they hit the maximum amount.
Here are some of the hundreds of charity projects involved:
Since the annual challenge launched in 2008, the Christmas Challenge has raised over £71 million for more than 2,500 charity projects.
It was founded by entrepreneur and philanthropist Sir Alec Reed CBE and has dozens of partners who have pledged the extra funding.
Dozens of charities have signed up to the scheme, and you can filter them by which area they work in to find the charities working in areas you particularly want to support.
For example, here are some of the categories:
- Overseas aid
This video explains how it all works:
You can find the website and donate here.
Go, go, go!