Love the intricacy of mehendi (Henna) designs.
Well it looks lovely on walls too. Here are some inspiring pictures.
You could draw it free hand and fill it with colour or if you do not have a steady hand you could used stencils like used here
Get tips on how to go about stencilling here
http://bit.ly/TvScPr. Fairly simple and amazing results. Why not give it a try.