When friends look at all the apps I have on my iPhone (about 260 at last count) they openly wonder why I have them all. I often wonder that myself. The answer is simple: I’m lazy.

I have them because I research and actually use an app before I talk about it my columns, then I get busy with something else and forget to purge the app. Often, however, I find the app is actually useful and I’ll keep it intending to play with it some more, but the opportunity to do so seldom comes. So, they accumulate.

I do have a core group of apps that I use a lot, depending on the device. On my iPhone that core group includes many of the apps that came with my iPhone even though I own arguably better alternatives. They are: iMessage/SMS, Photos, Safari, Maps, Music, Calendar, and Contacts. The other core apps include Camera+ , Instagram, and eWeather HD. Everything else I could probably live without, but there is another group of apps that I don’t use nearly as often, but am glad I have. They are those that are sometimes fun, often useful, and free. Here’s three such apps that I believe should sit on your iPhone and collect virtual dust until you need them, but you may be surprised how often you’ll dust them off.

Glympse: With iOS 5 and iCloud, Apple gave us Find My Friends, an interesting app that lets you and your friends and family keep track of each other. Apple wisely chose not to make this a built-in feature, given how rightfully touchy people can be about their privacy. Even if you have the app you don’t have to let people know your whereabouts. But there are times when you do want people to easily locate you. Maybe you’re meeting friends and you want them to know where you are waiting. If those in your group allow it you can see where they are, and they can see where you are. No one has to waste time searching for each other.

The problem with Find My Friends is that you have to have an iOS 5 device and an iCloud account to use it. Many of my friends and family have iPhones, but not all. That’s where Glympse come in.

Like Find My Friends, Glympse lets you see where your Glympse using friends are, but only if they want you to see them and for however long they want to advertise their locations. Unlike Find My Friends, Glympse is platform agnostic. There’s a Glympse app for Android, Windows Mobile, Blackberry, and, of course, iOS.

What’s also cool about Glympse is that you don’t need an account to get the location of your Glympse using friends, though you do need an account to send your location. The app uses SMS to send a message containing a link to a map showing your locale. You have full control over. You can set the duration of the link and how often it updates and the link can be cancelled at anytime. Even better, the map shows your speed and direction to your friends, making rendezvous much easier to coordinate.

According to the developer, Glympse does not monitor your whereabouts and can’t if you have no active Glympse sessions.

It’s not an app I’d use continually, I really don’t want people to know where I am all the time, but it is an app I can definitely use from time to time.

Action Movie FX: Here’s one that I don’t need and definitely don’t use a lot, but is sure is a lot of fun. Action Movie FX puts you or who ever you choose in the center of some really cool movie effects.

Let’s say your darling daughter is idly playing with her dolls. She is the picture of wholesome sweetness and you use your iPhone to take a memorable movie.

Ahh, there she is. So adorable. But wait! Some sinister ne’rdowell has lined her up in his missile sight. OH! MY! GAWD!

INCOMING!!!!!

Action Movie FX lets you capture create that moment. The free app, developed by Bad Robot, the same folks behind many of todays Hollywood action flicks, includes the missile strike and car crash effects that you can add to any movie you shoot with your iPhone. Other effects, sold in sets of two and cost US$0.99, include Airstrike/Firefight and Tornado Action/Downed Chopper.

I don’t shoot movies much, but Action Movie FX makes me wanna.

Redbox: OK, here’s the situation. You’ve had a rough day at work and all you want to do is go home, order pizza, and watch a movie. As you pack to leave your mouth waters at the thought of hot pizza, but then you pause. You realize you have no idea what to watch.

Well, if you have the Redbox app you could see what’s available at the many Redbox kiosks on your route home. If you find something you like you can reserve it and pick it up when you stop to get pizza.

It’s cheap. It’s easy. It’s on the way. The app is free and does a great job helping you pick a flick. You won’t use it all the time, but at the end of a long and tiring day you’ll be glad it’s there.

And that’s a wrap for this week.

If Redbox doesn’t have what you want then check out these free TV episodes, with direct links, available on iTunes. There’s bound to be something you’ll want to watch.