Indonesia Influence

There are tons of references related to Indonesian culture in the Nichijou series.

Sepak Takraw

Sepak takraw, Malaysia

In one episode Mio wakes up late because her alarm clocks not working. Looking for her mother, she finds a note by her mother saying that she's out playing sepak takraw (a traditional malaysian game). What flashes in Mio's mind shows her understanding of the sport. However, that might be the only thing she knows because she doesn't respond to Yukko's morning greeting which is Indonesian.
Reference to sepak takraw had been decided since Nichijou Prototype.

Indonesian

Bahasa Indonesia is a language used by Indonesians.

Selamat Pagi

Yukko says selamat pagi

Selamat Pagi (スラマッパギ Suramappagi), meaning Good Morning in Indonesian. This is Yukko's morning greeting. Yuuko's greeting is always blurry to Mio and Mai.

the detail of selamat pagi

Selamat Malam

Mai says selamat malam

Selamat Malam (スラマッマラム Suramammaramu), meaning Good Night In Indonesian. Mai's response to Yukko's morning greeting.

Selamat Tinggal

Yukko says Selamat tinggal

In Indonesian, this means Goodbye. In Episode 7, Yukko, Mio, and Mai run towards a train that is about to depart. Yukko is the only one 'safe' while the other two look on from the other side of train door. Yukko says selamat tinggal (セラマーティンガ"ル" Seramattinga"ru") with the last consonant l pronounced as ru(ル). This fact reveals that Yukko is not that proficient in Indonesian.

Bear as Beruang (disputed)

There is a speculation about a(n) Indonesian pun in Episode 2, Part 5. So far, there has been no confirmation whether the pun was intentional and someone somehow saw it as a straight Japanese pun.

Note from GangBunTu:

Am I the only one here that gets the pun as japanese pun instead of Indonesian pun? "aru toki ha kuma, soshite mata aru toki ha~a- ku- ma" which as a pun it could mean "sometimes i'm a bear, other times i'm a devil" which is shown as she takes mio's money I dunno, even if the show did involves parts of Indonesian as their randomness I still think this is a Japanese show aired in Japan. I think you're overthinking this since I doubt they make this as pun that only Indonesian people understand.

While pocketing Mio's money, her elder sister said this phrase :

• Japanese : ある時はクマ、そしてまたある時は…ク-マ
• Romaji : aru toki wa kuma, soshite mata aru toki wa- ku-ma

• English translation : Sometimes I'm a bear, and other times I'm a be-ar.
• Indonesian translation : Kadang-kadang aku ialah beruang, dan kadang-kadang aku ialah ber - uang.

In Indonesian, bear is beruang, while (noting ク-マ = ku-ma → be-ar) it became Ber - Uang (Uang, pronounced similarly to "wang" which means "money"), which sounds oddly similar to "berwang", meaning "to have money"..
Putting these together, we'll have: "sometimes I'm a bear, other times I also have money".
Yoshino uttered the 2nd phrase at the time when she was pocketing Mio's money.
So, was the pun intentional or just a weird coincidence?

Bear as Have Money
There are ugly debates in the comments section, kindly ignore them

Gamelan

This Easter Egg was brought to light by user mikoo at animesuki forum. It appears in several forms throughout the series, like in episode 7 below:

The text in the marked poster is ガムラン (gamuran = Gamelan), one of the Indonesian's traditional musical instruments.

To be more precise, since there are lots of tribes in Indonesia, gamelan is a traditional musical instrument of Javanese and Balinese tribes..

Soeharto

In the "Chic Things" segment in Episode 10, there is a man eating sushi with his bare hands who resembles Indonesia's second President, Soeharto.

Soeharto in Nichijou.

Soeharto in Memoriam.