97th Birthday Party Challenge

So my current project is a very special birthday party for a very special lady: my Granny! It combines a few of my favorite things (cue Julie Andrews singing softly in the background now): parties, party planning, travelling (especially going home) and Granny, who is my favorite of all. The party itself presents a couple of small challenges, plus I am proposing a challenge of my own just to make it even more interesting!
First, the inherent challenges:
1) Granny, as fabulous as she is, is turning 97 years old. She's had 96 birthdays and is not into making a big deal of herself. She is not a fussy or elaborate person at all. She is a very laid-back lady. She is gracious and fun-loving and will love and appreciate anything I put together, but I want to create something that is perfect for her and will not overwhelm or embarrass her.
2) This is the big one! The party will be at the nursing home where Granny lives and will have to fit into their schedule and their routine. Since Granny doesn't get around so well (that seems to happen when you're pushing 100 years old), I'm choosing to have her party at the nursing home so she does not have to go out and about and have trouble getting around. Plus, I want to include all of her new friends that live there. But...I don't know how many people that will entail, their cognitive and physical abilities and limitations, and any other restrictions there may be.
3) Her birthday is July 17 and I will be getting into town late in the day on July 14.

So that's a fun set of challenges to work with, but I'm upping the ante with a challenge of my own--I want to do all the decorations, paper, flowers, favors, etc for $25 or less.
Just for fun, here are the rules I'm setting for myself:
1) The $25 doesn't include the cake or any other food.
2) It's $25 to spend, not the estimated value of the products used (for example: sometimes on TV shows or for magazine articles, they'll use 25 of something that they purchased in a pack of 30, so they'll only count the per-item price of those 25 things in their total)
3) I'm not including sales tax in the $25, but the sales tax in my hometown is 10% and the sales tax where I live is 6.5% or 7%, depending on which city/town you're in.
4) I can use things that I or my dad already own as part of the party.

So there are my rules and my little challenge for myself. I'm going to get details on rules, guidelines, etc from the nursing home today and ask Granny what she wants the theme to be. Right now I'm thinking garden party with butterflies, 50's sock hop or beach bash. Details to come!