On Ermine, these 2 open-source projects:

For Graphic Adventures, tried ScummVM (http://www.scummvm.org/) -> Downloads -> Android, even though it's supposed to work with 2.2, won't install.

On the other hand, for Text Adventures / Interactive Fiction, Hunky Punk (http://sourceforge.net/projects/hunkypunk/) runs OK. Since it's in early development, the options are non-existent (fonts, colors etc.) but it works with most Z-games (samples included), supports the on-screen keyboard and screen rotation in any direction.