looking for a simple calendar for my form, none of the widgets work for my needs.

I don’t need this calendar to integrate, or anything fancy. The applicant filling out my form needs to simply check, mark, or highlight several dates that they can work for me. Is there a way to create a calendar like this? Once the applicant submits their form I want to be able to see what dates they checked or marked. Also, is there a css code that i can inject to make more than 3 horizontal columns for the radio buttons? Please let me know, I’ve become stuck on this.