Figure out who it is, call or email them, and apologize for not spending enough time with them recently. Tell them you love them and make no excuses OR explanations for any absence or distance. Instead, tell them to come over and spend the night with you this weekend or ask to come over to their place and do the same. Bring chocolate, beer or wine, junk food of some sort, maybe even ice cream. Insist that the only appropriate attire is pajamas. Take them their favorite magazine, coffee, or rent their favorite movie.
If you have little money to spend on these things, that's okay. Wake up before they do the next morning and make them breakfast, then clean up their kitchen so they don't have to. Do it anyway because you love them, and make sure they know it. Reaffirm that you love them and need them, and that you would be a wreck without them.
Make this your new ritual.