Learning something new together
It would be a great idea to learn something new with your couple. This will give both of you a valid reason to spend more time together and this works better for working couples who struggle to find time for each other. This could be learning a new language together. You may even enroll in a dance course together. If both of you are the adventurous types, and have time to spare, opt for a course in scuba diving or bungee jumping.
Giving a culinary surprise/sharing responsibility of the kitchen
It would be a great idea to give your spouse/partner a culinary surprise sometimes. On a weekend you may don the hat of chef at home and cook up dishes when he/she least expects it. Use the web resources to your advantage in this regard. Similarly, you may try sharing responsibilities in the kitchen in a regular and periodic way. You may cook every Saturday or Sunday.
Re-living old and cherished memories
This works very well for couples who entered conjugal life after being smitten by cupid. Every couple has some fond memories of time spent together in pre marital life. It would be a nice idea to indulge in things that you did together before tying the knot. Based on your situation and past, it could include things like eating at specific restaurants or going to amusement parks together or more adventurous stuffs! You may choose the upcoming wedding anniversary to repeat doing things you did and enjoyed in the past.
Where it all leads to?
Of course, there are many other ways to add spark of passion to your relationship and strengthen it. It depends on your specific situation, likings and mutual preferences etc. Sometimes, it makes sense to think creatively and come up with an unusual idea to amaze your spouse.