して います vs. しますwhen asking if someone plays a sport

Hello,
I have a question from module 4.8.  

Do you play any sports?
なにか スポーツ を して います か？/ Nanika supōtsu o shite imasu ka?

I like to try the translations myself before looking at the correct translation, and for this sentence, I put:
なにか スポーツ を します か

My understanding is that して います か would be more like saying "are you playing any sports" and that します か would be "do you play any sports" so I'm confused.   

The same question goes for:
はい、サッカーをしています  (isn't this "I am playing soccer")
はい、サッカーをします (I play soccer)

Both of these sentences are used on the page, but each have the translation "I play soccer" so I'm confused as to when to use which one.

A little further down, the reverse seems to happen:
こんばん　うち　に　だれか　きます　か？ / Konban uchi ni dareka kimasu ka
Is somebody coming to the house tonight?

I don't understand why it wouldn't be:
こんばん うち に だれか きて います か / Konban uchi ni dareka kite imasu ka 
The person is "coming" so wouldn't that use the ~te form?

I guess I'm completely missing something about the ~te form here.

Thank you for any insight you can offer! :-)

Hi エリニ、if you have the Genki books, this grammar is covered in Genki I Chapter 7.1.
The book describes three categories of verb where the "sense" of the verb determines if you need the 〜ている construction.

[These three categories are copied from Genki]
1. Verbs that describe continuous states.
2. Verbs that describe activities that last for some time.
3. Verbs that describe changes that are more or less instantaneous.

The Genki book skips over group #1 verbs, noting that いる and ある do not use the 〜ている construction.

For verbs that belong to #2, (たべる、よむ、のむ), this will mean an action in progress. 
Ex: ピーザを　たべています。{I am eating pizza (right now)} Note that this isn't the same as "I eat pizza (in general)" in this case.

These are also verbs that would tend to be related to a person's occupation or habit, so the playing of sports falls in this category.

Ex: 大学に勤めています。{だいがくにつとめています。} [I work in a university.]

#3 verbs describe a "change of state", so things like "being married" and "having children" fall in this category, so a 〜ている for a #3 verb "sense" wouldn't mean that they are  getting married or having children {being in labor} right now. Personally, I question the "change of" part of the Genki description, but their explanation is that one hasn't been married or have children always, so for them, it's a change of state or situation.

So, even though in English, we would say "he/she is married" in Japanese, it would be:

ジョンーさんは　結婚しています。ジョンーさんは　けっこんしています。} [John is "being in marriage state/situation." / John is married.}

Something to note here is that things like wearing clothes/jewelry for the day  fall into this category, so we would say:

千と千尋の神隠しのＴシャツ を着ています {せんとちひろのかめかくしのＴシャツ をきています。} [I wear/am wearing a Sen and Chihiro: Spirited Away T-shirt.]

My two cents/Disclaimer: I would put the "wearing clothes" and "(state of) being married in Category #1, but Genki puts these "states" in the same category as being overweight and having money (Category #3), so I don't know why there's a distinction being made.

So, in your sentence, you are asking if someone is coming "in general", so it doesn't fall into "action in progress"rule of a #2 verb.

Thank you very much for the detailed answer, and I ordered the book.  It just arrived today so I can start referencing it!

It's definitely less exciting reading than Rocket Japanese, lol :-)

Haha, wait until Genki II when Mary and Takeshi start going out! :D

こんにちは (Konnichiwa) イ リ ニ  and toru e.

Thanks for your question! 

toru e has already given a great answer to this question but I just thought I'd add another little explanation. 

Just like toru e says, we can use 〜て　いる (~te iru) in a few different ways: the main one being to talk about what we are currently doing. For example, "eating" たべて　います (tabete imasu). 

However, we can also use this form to talk about activities we do on a regular basis: like hobbies or habits. This is why when we ask "do you play any sports," we use the 〜て　いる (~te iru) form instead of the 〜ます (~masu) form. 

It's the same with "I play soccer." By saying サッカー　を　して　います (sakkā o shite imasu) instead of サッカー　を　します (sakkā o shimasu), you can express that you play soccer on a regular basis: not just a one off.

We have recently released brand new Level 1 Language and Culture lessons, with far more in-depth explanations on how this form works and the different ways you can use it.

Here's the link to the lesson on 〜て　いる　(~te iru) if you want to check it out. It will definitely help you to get your head around how it works! 

https://members.rocketlanguages.com/members/japanese/lessons/5148/5-8-When-Something-Is-Happening

I hope this helped! Please let me know if you have any other questions.

べんきょう　を　がんばって　ください！ (Benkyō o ganbatte kudasai!)