If you need to meet with someone about something, just ask. There isn’t a person at Fractured Atlas who wouldn’t make time for a coworker if they needed something.
If you want to see someone’s calendar, share yours and ask for her to share hers in return. Use Zimbra to invite people to meetings, but before you schedule one ask yourself if everyone you are inviting is a necessary addition. Also, instead of always scheduling a 60 minute meeting in a conference room, be open to an invitee suggesting an alternative venue or method to discuss the issue — a quick chat on Flowdock, a walk around the block, or a trip to Madman Espresso for a cup of coffee.