Vertex at edges' intersection?

Say I have two edges in the same plane. They cross each other at some point. Is there an easy way of creating a vertex at their intersection so I can connect the edges to each other?

The knife will do it. Select one edge, then ‘K’ - ‘(Exact)’. Control-click on each end of the other edge, and ‘Enter’ to complete the cut.

Best wishes,
Matthew

Wow, cool! Thanks so much!