Happy Birthday Ianto!
First, the practical gift. A phone from 2344 set to pick up waves from the early 21st century. It's a brilliant piece of machinery with all sorts of awesome technical advances, but a note attached says that if Ianto attempts to take it apart to use the technology inside for other purposes, the Doctor has programmed it to explode.
Also, the Doctor has removed the manual from the box.
Second, the fun gift. Because the Doctor has a great sense of humor.