Network Widget on Main Blog

I'm running WP 3.2.1 in MultiSite mode with BuddyPress 1.2.10 installed on my main blog. I have generated a multisite blog especially for community use, that is running a proprietary theme not available to my other blog-creating members.

That theme generates some of its own widgets, and I need to run some of these widgets on my main blog and Buddypress installation. I know there's a way to do this, but I can't remember - do I put PHP code in a widget on my main blog, or some sort of shortcode; or is there a special plugin that accomodates this, etc. Any light anyone can shed would be much appreciated; my thanks in advance --