RX is the community's party and that means the larger the better. As you interact with others in your organization, consider inviting them. You might think, "Rock's not their job," but RX is not about Rock (yes we said that). Rather, it's about innovating in ministry. Nearly every role in your church can glean ideas, encouragement and relationships at RX.
Also, while you interact with others in the Rock community, be sure to ask them if they are planning to attend. Don't assume that they know about it or that they are coming. You'd be surprise how a small encouragement from you can have an impact on their plans.
Now let's get this party started... well 155 days ago.