Cast Adobe Illustrator shapes to SVG and then, perhaps as a second step, get them into Inkscape.

From the "Save As..." option under the "File" menu in Adobe Illustrator one may save a .svg file. If you open this file in Notepad you will see the SVG markup plain as day. From the "Open..." option under the "File" menu in Inkscape one may turn around and open up the thing Illustrator spit out.