You might also consider the following:
Couples Spa Day
Many spas offer couples packages that can have both of you getting a massage, soaking in a whirlpool tub, or even getting pedicures. Sometimes, these packages include a healthy meal or snack. And all of them can be quite relaxing, while at the same time serving as a good way to bond.
Breakfast in Bed
Even though it might be the old standby, breakfast in bed still makes for a great gift. Who doesn't like to roll over to find freshly baked muffins or pancakes with Maple syrup or some crisp bacon on a tray with a small vase filled with fresh flowers and a freshly pressed napkin?
A Gift of Jewels
Diamonds truly are a girl's best friend. When in doubt about what to get the woman in your life, go for diamonds or some sort of jewels. You can't go wrong with gold, especially nowadays. But even imitation jewelry, as long as it's your wife's style, can make for a nice gift. Take your cues from the rest of her wardrobe to decide what kind of jewelry she would like and could use.
Cooking and Cleaning
Nothing is sexier to a working mom (and they're all working) than a man who helps her around the house. She'll be swooning to see you in an apron and with a mop in your hands. Do all the cleaning and cooking for at least one full day. Liberating your spouse of these duties will make her feel like a true princess, and it will prove to you how much she really does for you and your family.
Bath Time
Everyone is looking for a little escape. Sometimes, all you can afford for a getaway is some time in the bathroom. Run a bath for your wife and let her lock herself in there for the evening. No questions asked. Refrain from that urge to knock on the door to ask her for the tenth time where your slippers are. You can find them yourself. Really.
Night Out
Marriage does not mean death. You must go on dates and woo each other long after your wedding. And Mother's Day is the perfect excuse to do just that. Make a date to paint the town red - or whatever color you prefer. Even a simple dinner in a nice restaurant just the two of you can put the spark back in your relationship and send the message that you truly care about this mom.
Family Beach Day
Mom might not want to spend Mother's Day without her kids. Know your audience and what the mom in your life would prefer. If she wants to hang with the whole family, then you might consider a day on the beach. Of course, this is only a good idea if the weather is ideal. But remember even a spring day can be a fun one on the beach. You can still picnic and fly a kite or take a walk even if it's too cold for a swim where you live.
Family Getaway
Whether you opt to take your wife on a vacation just the two of you or with the whole family, a vacation makes for a wonderful gift. The nice thing about this present is that everyone gets to have some fun. And you can all unwind together away from the hustle and bustle from your everyday life. What mom doesn't need to do that every now and then?