I don't know about shades but I once lived in an apartment that had screen stretched across the windows & stapled in place. There were lattice strips nailed over to hide the connection that were painted to match the window. None of those items should be too expensive & it looked great! ... View related article.
Have the kids dress up in Flamenco or other Mexican attire, serve tacos, have a cake that looked like a pinata or one of those Barbie cakes done up to look Mexican, give out folding fans as pary favors and be sure to have at least one pinata! ... View related article.