I would suggest building in team building into your culture if you want to encourage people to get to know each other, build trust, be happier at work, and go the extra mile.
The team will pick 3 approved charities and the winner of the jelly beans guessing game will pick one of the approved charities.
The main difference is everyone will gather on an online video conference call to announce the winner and have the winner pick the charity.
If you would prefer not to collect money, especially if you are a virtual team, you can create jelly bean jar and keep track of guesses.