Coffea Arabica is easy to grow indoors, makes a very attractive houseplant and if it likes you well enough, it will even rewards you with flowers and berries!
Grow your own Coffee, will take approx 4 years for first harvest. It is actually very easy to grow, indoors. This is surely worth a try for something different.
Passiflora ambigua or Passion Flower is a very rare Passiflora that grows very fast and becomes very big. The flowers have pink petals and sepals, the filaments are white streaked with red and purple. They measure 10-13 cm in diameter and spread a very unpleasant smell.